1. Technical Field of the Invention
The present invention refers to the weaving industry in general and, more specifically, to a method of manufacturing a two-thread yarn having a certain degree of elasticity for use in the weaving industry and to an apparatus for carrying out said method wherein a mono or multi-thread elastic yarn and a support yarn are fastened to each other, treated with a protective chemical film, dyed, stretched and set in order to provide a two-thread yarn having the desired elastic properties.
2. Description of the Prior Art
As it is widely known by those skilled in the art of weaving, since the first synthetic yarns were first developed approximately 50 years ago as a substitute for silk wool and cotton yarns, which production requires an extensive and rather lengthy process, the weaving industry has been trying to provide physical properties as close as possible to that of the natural yarns to these synthetic yarns.
With this purpose in mind, scientists in research and development centers all over the world have dedicated their efforts to combine the basic features of the synthetic yarns such as thickness, cross section, elasticity and others in order to provide a synthetic yarn which would result in a knitted or woven fabric having the same features of a fabric knitted or woven from a natural yarn.
A desirable feature of the fabrics manufactured from a synthetic yarn which can not be provided by a fabric made from 100% natural silk, wool or cotton yarn is a certain degree of elasticity, since these yarns have only a small amount of elasticity, if any.
However, providing a knitted or woven fabric having a precisely defined amount of elasticity is a difficult task, which has occupied the attention of researchers everywhere.
Presently, in order to provide a knitted or woven fabric having a certain degree of elasticity, typically an elastic yarn such as a mono or multi-filament elastic thread is used for knitting or weaving the fabric.
In the process of manufacturing a knitted fabric in a circular loom, said elastic yarn is typically used alone, that is, without being covered by a support yarn. In a circular loom the elastic yarn previously wound in bobbins is positioned in a feeding section of the loom and the elastic yarn is threaded with the support yarn made from a non-elastic material only at the entrance opening of the knitting needles. A typical circular loom has a capacity to handle approximately 90 bobbins of elastic and support yarns.
In the process of manufacturing a non-circular knitted fabric in an open warp loom, the elastic yarn is also used alone, that is, without being covered by a support yarn, the previously stretched elastic yarns being provided in bobbins. Approximately 1000 bobbins of the previously stretched elastic yarn are positioned in the feeding section of the loom and the elastic yarn is threaded with the support yarn in the knitting loom, the stretching of the elastic yarn being controlled by the feeding section.
Contrary to the above, when used in the process of manufacturing a woven fabric in an open warp loom, currently the elastic yarn is used only covered with a support yarn both as a warp thread to provide the resulting fabric with a certain degree of elasticity in its longitudinal direction, or as a weft thread in order to provide the fabric with a certain degree of elasticity in its transversal direction.
The use of an elastic yarn such as a mono or multi-filament elastic thread such as Lycra.RTM. for knitting or weaving a fabric having a certain degree of elasticity according to the state of the art, however, has the drawback that the cost of the resulting fabric is too expensive, due to the costs involved in manufacturing the covered elastic yarn in one case, and of the use of the elastic yarn alone, in the other.
An object of the present invention, therefore, is to solve this drawback of the prior art and it was with this problem in mind that the inventors of the present invention have developed the present method of manufacturing a two-thread yarn having a certain degree of elasticity for use in the weaving industry where a mono or multi-thread elastic yarn and a support yarn are fastened to each other, treated with a protective chemical film, dyed, stretched and set in order to provide a two-thread yarn having the desired elastic properties.
According to the present invention, the above and other objects and advantages are accomplished by the provision of a method of manufacturing a two-thread yarn having a certain degree of elasticity for use in the weaving industry comprising the steps of: providing at least one elastic yarn and one support yarn as a paired couple; applying a water-soluble thermosetting adhesive substance to said paired couple of yarns; fastening said adhesive coated paired couple of yarns to each other to form a two-thread yarn; and simultaneously stretching, heating and setting said elastic yarn and said support yarn paired as a couple to form the two-thread yarn.
According to a preferred embodiment of the present invention, said method additionally comprises the steps of applying a protective chemical film and a dyeing agent to the yarn while it is being fastened, drying the two-thread yarn comprised of said elastic yarn and support yarn, and of cooling the dried two-thread yarn after it leaves the drying chamber.
According to another aspect of the present invention, an apparatus for carrying out the method of manufacturing a two-thread yarn having a certain degree of elasticity for use in the weaving industry is also provided, said apparatus comprising: means for providing at least one elastic yarn and one support yarn as a paired couple; means for applying a water-soluble thermosetting adhesive substance to said paired couple of yarns; means for fastening said adhesive coated paired couple of yarns to each other to form a two-thread yarn; and means for simultaneously stretching, heating and setting said elastic yarn and said support yarn paired as a couple to form the two-thread yarn.
According to a preferred embodiment of the present invention, said apparatus additionally comprises means for applying a protective chemical film and a dyeing agent to the yarn while it is being fastened, a drying chamber for drying the elastic yarn and the support yarn paired as a couple forming the two-thread yarn and a cooling chamber to cool the dried two-thread yarn as it leaves the drying chamber.
The foregoing and other additional objects, features and advantages of the method for manufacturing a two-thread yarn for use in the weaving industry and of the apparatus for carrying out said method according to the present invention will be better understood by reference to the following detailed description, accompanied by schematic illustrations of the presently preferred embodiment of the invention, as shown in the attached drawings.